4.4 Telephone Numbers The functions dtmfdial.m and dtmfrun.m can be used to test the entire DTMF system as shown in Fig. 8. You could also use random digits (e.g., ceil (15.9 rand (1,22)+0.09)) in place of 1:16 in dtmfdial. For the dtmfrun function to work correctly, all the M-files must be on the MatLAB path. It >f=8000; tk=[A,B,C,D,D,#,,1,2,3,4,5,66,77,8,9]; xx=dtmfdial(tk, fs ); >soundsc (xx, fs) > > = L dtmfrun (xx, L, fs) ans = AABC#0123456789 Figure 8: Testing the DTMF system. is also essential to have short pauses in between the tone pairs so that dtmfcut can parse out the individual signal segments. If you are presenting this project in a lab report, demonstrate a working version of your programs by running it on the following phone number: 40789132#BADC In addition, make a spectrogram of the signal from dtmfdial to illustrate the presence of the dual tones